The present invention relates to a method for coating surfaces by treatment with at least one substantially paraffin-free aqueous formulation, comprising    (A) at least one copolymer having a melt flow rate (MFR) in the range from 1 to 50 g/10 min, which comprises, incorporated in the form of polymerized units,            (a) from 65 to 74.5% by weight of ethylene,        (b) from 25.5 to 35% by weight of at least one ethylenically unsaturated carboxylic acid,        and which is at least partly neutralized with alkali metal,            (B) at least one nonionic or anionic surfactant,    (C) at least one antifoam,    (D) if appropriate, at least one organic amine,    (E) if appropriate, at least one organic solvent.
The present invention furthermore relates to surfaces coated by the method according to the invention. The present invention furthermore relates to aqueous formulations which are particularly suitable for carrying out the method according to the invention.
Surfaces, for example metal surfaces, are coated in numerous cases in order to protect them from environmental influences. Finishes may be mentioned by way of example. Such coatings are also referred to as permanent coatings since they are intended to display their protection for a relatively long time, for example at least one year.
On the other hand, however, it is also desired to provide surfaces by coating with shorter protection, for example from dirt and in particular from fingerprints. Such protection may be effective for a few days or weeks or even less and need not be complete, and may also result in retardation of soiling. However, the dirt, in particular the fingerprints, can then be removed by simply wiping off. Such a coating is also referred to as a temporary coating. Thereafter, the surfaces can be coated again.
In the choice of the coating material, paraffins are generally recommended in association with metal surfaces. In order to be able to apply paraffins to surfaces, in particular metal surfaces, it is desired to formulate them in water and then to apply them. Thus, one or more surface-active substances (emulsifiers, surfactants) are required in order to formulate the paraffin. For example, ethylene/acrylic acid copolymers are described in the literature as suitable surface-active substances.
However, paraffins have disadvantages when they are used for the temporary coating of surfaces. The effectiveness of paraffin-containing coatings lasts as a rule for a day or less and is therefore too short for many applications. Furthermore, paraffin-containing coatings frequently tend to smear and are therefore unacceptable for coating where cleanliness is important, for example metal surfaces in kitchens, in particular kitchen fittings and industrial dishwashers.
Many other coatings which, compared with coatings with paraffin, have the advantage of greater stability are difficult to remove, for example by strongly alkaline cleaning solutions, in the case of soiling.